Quantum dot micropillar cavities with SiO2 hard mask microlenses

We report finite difference time domain simulations of GaAs-Al0.95Ga0.05As micropillars containing single quantum dots with SiO₂ microlenses of differing shapes and heights, finding an approximately linear reduction in the numerical aperture and mode field diameter of the outcoupled emissions via the fundamental mode. This opens the possibility of modifying our previously reported direct-write lithography process to leave an amount of hard mask on top of the pillar, which could modify the light emitted from our single photon sources to be more efficiently coupled into an output single mode fibre.